foodborne disease outbreak tabletop exercise dubai, uae february 2014 these data are for training...

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Foodborne Disease Outbreak Tabletop Exercise

Dubai, UAEFebruary 2014

These data are for training purposes only and do not represent factual events

These data are for training purposes only and do not represent factual events 2

Objecti ves

• Understand the specific and intersecting role of laboratory and epidemiology – During cluster detection– During cluster/outbreak investigation– During outbreak deceleration and resolution

• Understand the key considerations for communication between laboratory and epidemiology during outbreak investigations


Overview

• Scenario with five parts– Short slide presentation for each section followed by

discussion

Time Section

20 mins Introduction

25 mins Part 1 (Detection)

25 mins Part 2 (Acceleration)

25 mins Part 3 (Deceleration/Resolution)

25 mins Wrap up


INTRODUCTION


Foodborne Disease Outbreak Investi gati ons

• Goals:– Immediate control of outbreak and prevention of illnesses– Provide opportunities to identify gaps in food safety

systems

• Effective investigations key to reducing burden of foodborne disease– Identify food vehicles and factors which lead to outbreaks

More food is centrally produced, so when something goes wrong, people get sick over a wide area

More food is sold fully cooked, so consumer just has to warm it

More food is eaten in restaurants, so more people have a hand in preparing our food

We import more of our food supply, so we depend on the food safety systems in other countries

Healthy animals can carry germs that make us sick

New technologies for producing, processing, and preparing foods

Foodborne Diseases: A Changing Landscape



Steps in investi gati ng an outbreak

1. Detect the cluster and assemble a team2. Gather descriptive information

a. determine etiology b. describe the outbreak by time, place, and person c. write a case definition d. conduct surveillance for more cases

3. Generate hypotheses4. Test hypotheses

a. design a study b. analyze the study

5. Determine how and where contamination occurred6. Prevent more illnesses7. Communicate


Cluster vs. Outbreak

• Cluster = the occurrence of more than the expected number of people diagnosed with a certain disease within a specific group, geographic area, or period of time

• Outbreak = a cluster of cases linked by a common exposure/event

• Not all clusters are outbreaks


Lessons Learned in Investi gati ng Multi state Foodborne D isease Outbreaks

• Case patient demographics (age, sex, ethnicity) and geographic/ temporal distribution provide critical clues about the source

• Clusters of cases at restaurants, events, food shopping venues are key– Help narrow the focus– Facilitate traceback to find commonality across clusters identified

• It is not just asking ill people what they ate, but also understanding how food is prepared at the menu/ingredient level

• Industry groups can provide information to help shape hypotheses


E. coli O157

• Shiga-toxin producing E. coli (STEC)

• Colonizes intestinal tract of ruminants

• Diarrheal illness– Can be severe in children and elderly– Hemolytic-uremic syndrome (HUS) (a type of kidney failure)

• Incubation time: The time from eating the contaminated food to the beginning of symptoms is typically 3-4 days

• Commonly implicated vehicles: ground beef, leafy greens, and unpasteurized dairy


Khati b

• Population size: 63 million• Capital city: Khatima, population 1 million• Ministry of Health headquartered in Khatima• Breakdown of municipal structure

Country X

Province

Community

Sina


Laboratory Capacity for E. coli O157 Testi ng in Khati b

• Provincial laboratories and major hospitals institutes have capability to test stools submitted for the presence of Shiga toxin-producing Escherichia coli (STEC).

• National Health can conduct DNA "fingerprinting" with pulsed-field gel electrophoresis (PFGE)


PART 1: DETECTION


Outbreak Detecti on

• 19 April 2014: Block Health officer in Sanand block was informed by an local health worker in Andej village of cluster of 6 children with bloody diarrhea• 2 children have already died

• Rapid response team consisting of district level health officials as well as clinicians and experts from the local Medical College have been dispatched to the field on the same day.


Preliminary Case Patient Demographic/Clinical Info (n=6)

• Illness onsets during 5 April to 20 April• Median age = 7 years; Age range: 6 to 8 years• 67% (4/6) are female• 5 hospitalized• 3 with Hemolytic Uremic Syndrome (HUS) • 2 deaths• Preliminary laboratory testing from 2 cases with

HUS indicates E. coli O157 infection


Preliminary Case Defi niti on

• Illness with laboratory confirmed E. coli 0157 OR Hemolytic-uremic syndrome (HUS) OR blood diarrhea among a resident Khatib since 1 April 2014


Noti fi cati on of Health Providers

• An alert is sent to local hospitals, clinics, and health workers in Khatib to report any suspect cases of illness


17 cases f rom 7 prov inces , as of 19 Apr i l

AndejVillage


Cases by Date of Report - 15 Feb to 19 April 2014 (n=17)

Case Patient Demographic/Clinical Info• Median age = 22 years • Age range: 2 to 65 years

< 5 years = 13%6 to 17 years = 30%18 to 50 years = 43%50+ years = 4%

• Female = 71%• 10 hospitalized

• 3 with Hemolytic Uremic Syndrome (HUS)• Two deaths

Date of report


Panel Discussion – I

• Perspectives and next steps as of 19 April 2014? – Is this an outbreak?– Laboratory / Epidemiology

• Is case definition appropriate?• What other case-finding methods should we consider?• How frequent/what are the logistics of how information exchanged

between lab and epi?• How helpful would it be to request additional lab testing?• What is helpful for lab to know to better aid epi investigation? Vice

versa?– Communication:

• Public health notification? – Local– National– International

• Does the public need to be informed– If so, what/how?


PART 2: ACCELERATION


Next Steps: Hypothesis Generati on

• Rapid response team requested food/exposure history from patients parents/care givers via “supplemental” E. coli O157 questionnaire that includes a 5 day food history plus specific questions on:– Unpasteurized milk and dairy– Leafy greens (spinach, lettuce), sprouts– Animal contact– Shopping & eating locations– Attendance at events– Travel history

– A notice sent to other Districts to complete supplemental questionnaire on any illnesses meeting the case definition

• Completed supplemental questionnaire requested by fax to District Health Officer which provides to National Level Health Authority


Summary C l in ica l/Demographic Informati on as of 9 May 2014

• 56 cases in 14 provinces– 21 hospitalizations, 3 with hemolytic uremic syndrome (HUS); two

reported deaths

• Unusual age distribution– Heavily skewed toward 15-49 (75% of cases)

– More females (~70%) than males

• Illness onset range: 27 February – 20 April


Lab Informati on as of 9 May

• 19 cases have confirmed E coli O157:H7 Infection• DNA "fingerprinting" with pulsed-field gel

electrophoresis (PFGE) performed at the National Reference Laboratory, found:– 17 (89%) had same rare pattern, EXHX01.0026 /

EXHA26.0005– 2 (11%) other patterns

• All isolates with EXHX01.0026 / EXHA26.0005 pattern are positive for stx2 only (a marker for more sever disease)


Case Interview Informati on as of 9 May

• A total of 25 questionnaires received• Cases report eating: – Eggs (92% 23/25), nuts (88% 22/25), lamb (88% 22/25),

yogurt (88% 22/25), chickpeas (84% 21/25), tomatoes (76% 19/25), eggplant (64% 16/25), cucumber (64% 16/25), milk (76% 19/25), oranges (56% 14/25)• No single brand or type predominates for any of these foods

– No other food eaten in unusual frequency • Cases eat food bought from many different markets –

none in common• No history of travel or attendance at a common event


Case Interview Informati on as of 9 May

• Four unrelated cases (from different families) reported eating a meal at the same Anganwadi (local community center)

• Meal dates on 2 April and 3 April• No other cases report common food exposure


A Cluster in Another Province

• On 10 May, Razi Province reports a sudden cluster of cases of HUS presenting at local hospitals– No previously reported cases– Does not neighbor any provinces with reported cases

• Total of 18 hospitalized cases with bloody diarrhea, 4 with HUS– Preliminary laboratory testing from 2 cases with HUS

indicates E. coli O157 infection• Median age is 19 years, 75% are male• Illness onsets range: 7 April to 16 April


64 cases in 11 provinces, as of 10 May


Panel Discussion IIa

• Is this an outbreak?• Is the HUS cluster in Razi Province part of the

larger investigation?– What information do you want to know from lab?– What information do you want to know from epi?

• Next steps, right now?– Lab– Epi


PART 2: ACCELERATION PART 2


Revised Case Defi niti on

• Illness with laboratory confirmed E. coli 0157 OR Hemolytic-uremic syndrome (HUS) since 15 Feb 2014


Cluster Identified (April 19)

Infections with E. coli O157:H7 by Date of Onset, 15 Feb to 10 May 2014 (n=64)

Infections with E. coli O157:H7 by Date of Report, 15 Feb to 15 May 2011 (n=56)

Cluster Identified (April 19)



C a s e F o o d C o n s u m p ti o n I n f o r m a ti o n a s o f 1 5 M a y ( n = 4 0 o f 6 4 )

• Exposures reported by >50% of cases– Nuts: 82%

• No single type of nut predominates– Chickpeas: 84%

• no single type predominates– Yogurt: 86%– Four unrelated cases eating at the same Anganwadi were

asked about the meal they ate there– All had a meal consisting of rice, dal, cucumber salad, and raita


HUS cluster in Razi

• Health officials interviewed 6 of 8 hospitalized cases– 3 reported eating at 2 different sandwich shops

serving kofta and shawarma• Shop A: veal/lamb kofta with all toppings• Shop B: one chicken shawarma with all toppings; one

lamb kofta, but never eats any of the vegetable toppings

Lab results for HUS cluster

• PFGE results indicate that patient isolates from the HUS cluster match the main outbreak pattern (EXHX01.0026 / EXHA26.0005)

• Toxin profile also matches (stx2 only)



Panel Discussion I Ib

• Is this an outbreak?• What is the case definition?• What does the shape of the epi curve tell us about the hypothesis (if

anything)?• What type of epidemiologic follow-up?

– Analytic studies– Comparison studies (what)

• Can engaging industry be helpful? How?• Food testing

– What do we test, if anything?

• Communication– Lab/Epi– Public health notification?

• Local• National• International

– Does the public need to be informed• If so, what/how?


Part 3: Resoluti on/Decelerati on


Case defi niti on

• Confirmed– A person with E. coli O157 infection with illness

onset from February 15, 2012 to present, and– with isolate matching PFGE XbaI pattern

EXHX01.0026• Suspect– A person with either HUS or diarrheal illness

confirmed as Shiga toxin-positive based on laboratory testing (PFGE pending or not available)


Menu-level Comparisons

• A total of 7 cases in Razi report eating sandwich wraps from 2 different shops– Shop A: 2 cases report eating veal/lamb kofta with all toppings; 2 cases

report eating chicken shawarma with all toppings• meal dates between 6 April and 10 April

– Shop B: two cases report eating chicken shawarma with all toppings; one lamb kofta, but never eats any of the vegetable toppings• meal dates between 4 April and 7 April

• A total of 9 cases in Andej Village reported eating a meal at the Anganwadi (local community center)– All had a meal consisting of rice, dal, cucumber salad, and raita

– Meal dates either of 2 April or 3 April


Ingredient-level Comparisons

• Recipes for each dish served at the sandwich shops and Anganwadi obtained– Different proteins used in the meals eaten by ill

people– Common: yogurt sauce on shawarma and raita at

Anganwadi)


A Hypothesis!

• Could contaminated yogurt be the source of this outbreak?


A Hypothesis!

• Could contaminated yogurt be the source of this outbreak?– What are the ingredient in yogurt sauces served in

the sandwich shops and the raita served in the Aganwadi?


Yogurt Sauce Ingredients

• Aganwadi (raita)– Yogurt, brand A– Cumin– Cucumber,

shredded– Salt

• Shop A – Yogurt, brand A– Cucumber, diced– Garlic, fresh– Salt

• Shop B– Yogurt, brand A– Mayonnaise– Cumin– Cucumber,

grated– Garlic, grated– Salt– Sugar– Pepper


Raita/Yogurt Sauce Ingredients

• Anganwadi– Yogurt, brand A– Cilantro– Cucumber,

shredded– Cumin– Onion– Salt

• Shop A– Yogurt, brand A– Cucumber, diced– Garlic, fresh– Salt

• Shop B– Yogurt, brand A– Mayonnaise– Cumin– Cucumber,

grated– Garlic, grated– Salt– Sugar– Pepper


Engaging Industry

• Yogurt– Brand A yogurt makes up 92% of the market share

• Cucumbers– Cucumbers grown in 2 southern provinces this time of

year– 2 large farms (Farm Alpha and Farm Zeta)

• Sell commercial volume cucumbers; farms do not sell cucumbers to retail grocers

• 4% of cucumber crop was exported to 3 neighboring countries

– Farm Alpha closed since 1 March due to workers’ strike


Food testi ng

• Based on ingredient-level comparison, lab undertakes targeted food testing of – Brand A yogurt – Cucumbers from Farm Zeta


Food Testi ng Results

• Two weeks later, 30 May– Cucumbers • PFGE outbreak strain (EXHX01.0026 / EXHA26.0005)• Toxin profile: stx2

– Yogurt• STEC (+); PFGE different from outbreak strain• Toxin profile: stx1 and stx2


Panel Discussion III

• Is this an outbreak?• Significance of the food testing results?

– What if cucumbers were negative?– STEC(+) yogurt action point?

• Is the outbreak over?• Communication:

– Does the public need to be informed• If so, what/how?

– Public health notification to local, international agencies• If so, what/how?

• Debriefing the investigation team:– Logistics, evaluation, lessons learned, next time


Investi gati on of Farm Zeta• A large dairy farm was directly adjacent to the cucumber-growing

area.– Testing of water from the sewage lagoon identified E. coli O157:H7 with a

PFGE pattern indistinguishable from the outbreak strain (EXHX01.0026 / EXHA26.0005)

• There was evidence of water pooling in a low-lying part of the cucumber field close to the dairy farm.

• The farmer reported several episodes of unusually heavy rains in the weeks before the first cases were reported and then during the period when cucumbers were harvested from this field (late March and early April).

• A recommendation was made to the farmer to not use harvest areas prone to flooding


What is the conclusion of this outbreak?

• Large, multi-prefecture outbreak of E. coli O157• 64 cases in 11 provinces• 39 (61%) hospitalized; 2 deaths

• Illnesses were most likely caused by consumption of contaminated cucumbers served at restaurants/outside the home

• Cucumbers were grown by Farm Zeta


64 cases in 11 provinces, as of 30 May


Final epi curve of cases by date of illness onset, 15 Feb to 19 May 2011 (n=64)


Wrap up• PFGE aided in confirming and defining the scope of an

outbreak

• Industry aided understanding market share and product distribution

• Routine communication with lab and epi group critical to success of the outbreak

• How do we sustain lab/epi communication and collaboration?

• What activities can you implement right now to strengthen lab-epi communication and collaboration?

foodborne disease outbreak tabletop exercise dubai, uae february 2014 these data are for training...

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